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When saving, how can you check if a field has changed?
...y, you want to override the __init__ method of models.Model so that you keep a copy of the original value. This makes it so that you don't have to do another DB lookup (which is always a good thing).
class Person(models.Model):
name = models.CharField()
__original_name = None
def __i...
When to use reinterpret_cast?
I am little confused with the applicability of reinterpret_cast vs static_cast . From what I have read the general rules are to use static cast when the types can be interpreted at compile time hence the word static . This is the cast the C++ compiler uses internally for implicit casts also.
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What does && mean in void *p = &&abc;
I came across a piece of code void *p = &&abc; . What is the significance of && here?
I know about rvalue references but I think && used in this context is different. What does && indicate in void *p = &&abc; ?
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How to wrap text in LaTeX tables?
I am creating a report in LaTeX which involves a few tables. I'm stuck on that as my cell data in the table is exceeding the width of the page. Can I somehow wrap the text so that it falls into the next line in the same cell of the table?
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How do I quickly rename a MySQL database (change schema name)?
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For InnoDB, the following seems to work: create the new empty database, then rename each table in turn into the new database:
RENAME TABLE old_db.table TO new_db.table;
You will need to adjust the permissions after that.
For scripting in a shell, you can use either of the follow...
How can I merge properties of two JavaScript objects dynamically?
I need to be able to merge two (very simple) JavaScript objects at runtime. For example I'd like to:
63 Answers
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Getting realtime output using subprocess
I am trying to write a wrapper script for a command line program (svnadmin verify) that will display a nice progress indicator for the operation. This requires me to be able to see each line of output from the wrapped program as soon as it is output.
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SQL join: selecting the last records in a one-to-many relationship
Suppose I have a table of customers and a table of purchases. Each purchase belongs to one customer. I want to get a list of all customers along with their last purchase in one SELECT statement. What is the best practice? Any advice on building indexes?
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preventDefault() on an tag
I have some HTML and jQuery that slides a div up and down to show or hide` it when a link is clicked:
11 Answers
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Keeping it simple and how to do multiple CTE in a query
I have this simple T-SQL query, it emits a bunch of columns from a table and also joins information from other related tables.
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